1. Technical Field
The present invention relates to a device for controlling animation of an image displayed on a display.
2. Background Art
Conventionally, for users to operate household electrical apparatuses such as a television set, a video player, and a DVD (Digital Versatile Disc) player (hereinafter, referred to as an apparatus), the display of the television set or the like uses a GUI (Graphical User Interface) application program for displaying an image by which the operation is received (hereinafter, referred to an application). Moreover, at present, applications including animation have been increased. In animation, a state of the animation part (for example, at least one of the position, the size, the shape, the color, and the degree of transparency) is gradually changed at a constant interval of time and the changed animation part is displayed. The constant interval of time is determined in advance for each display, and specifically determined by a refresh rate of the display called a vertical synchronous frequency set for the display. The animation part is an image (GUI part) displayed as a target for the animation by the application.
Namely, in order to implement the animation according to the application, an animation control device provided in the conventional apparatus performs processing to refresh a content of drawing at every constant interval of time. For example, when the vertical synchronous frequency set for the display is 60 Hz, the content of drawing can be refreshed only 60 times per second in the display. In this case, the constant interval of time is 16.6 ms. Hereinafter, the constant interval of time is referred to a refresh interval.
FIG. 11 is a drawing showing an example of animation according to the conventional animation control device.
The conventional animation control device executes an application. By the application, as shown in (a) of FIG. 11, while an animation part 202 displayed on a display 201 is enlarged over a predetermined time (drawing processing time), the animation part 202 is moved in a predetermined drawing direction (the arrow in (a) of FIG. 11) to be displayed as an animation part 203. At this time, in order to implement the animation, the animation control device performs the processing to refresh the content of drawing at every refresh interval during the drawing processing time, as shown in (b) of FIG. 11. Namely, when the animation is started and the refresh interval has passed, the animation control device enlarges the animation part 202 slightly and moves the animation part 202 to the drawing direction. Subsequently, every time when the refresh interval has passed, the animation control device repeatedly performs the enlargement and movement of the displayed animation part 202 (the processing to refresh the content of drawing). Thus, the animation part 203 is displayed on the display 201 when the animation is started and the drawing processing time has passed.
The application is set so as to perform the processing to refresh the content of drawing during the drawing processing time by the number of times of the refresh interval that passes. For example, when the vertical synchronous frequency to be set for the display is 60 Hz, and the drawing processing time until the animation part 202 is moved and displayed as the animation part 203 is 2 seconds, the application needs to be set so as to perform the processing to refresh the content of drawing 120 times.
The processing to refresh the content of drawing is performed at every refresh interval to implement the animation. Namely, the animation part 202 is moved during the drawing processing time in the drawing direction, and finally displayed as the animation part 203.
Here, now, for example, the same application distributed by a network or the like may be performed in a plurality of different apparatuses. However, the number of the animation parts to be moved at every refresh interval of the display may be different for each of the animation control devices provided in these apparatuses, for example, because the CPUs (Central Processing Units) of these apparatuses have different clock frequencies. Even in the apparatuses having the CPU of the same clock frequency, the number of the animation parts to be moved may be different according to the state of use of the CPU.
Accordingly, in the prior art, an animation control device has been provided in which quality of display of the animation is switched between high quality and low quality according to a CPU usage rate (for example, see PTL 1). The animation control device in PTL 1 changes frame rates of icons, menus, and moving pictures when the CPU usage rate is high, and reduces the CPU usage rate.